Vigen, one of Iran's most famous singers, came from the country's Armenian community. He was loved by all Iranians in spite of the fact his faith was different from the vast majority. He died recently, but remains a legend.
The number of Armenians, Iran's largest Christian minority, was estimated at about 300,000 in 1979. It has declined in recent times but remains culturally important.
Mardo Soghom, the director of RFE/RL's Radio Farda, is Armenian by origin but grew up in Isfahan, in central Iran.
"The 400-year history of the Armenian community in Iran is perhaps the greatest example of religious tolerance and peaceful coexistence, even at the time when the country experienced isolation and socio-economic backwardness," Soghom said. "In the 20th century, as the country modernized, the Armenian community thrived both economically and culturally. After the revolution, dislocations and restrictions affecting the general population also created hardships for Armenians, nearly half the community left Iran. Some discriminatory policies and restrictions came into effect, but still community rights are generally protected."
Armenians have two seats in the Iranian parliament but continue to face cultural, social, and administrative difficulties. They report discrimination in finding work, and just a few Armenian schools are fortunate enough to have an Armenian schoolmaster.
The Assyrian Christian population is estimated at some 10,000. They have one seat in the parliament.
Iran is also home to a small number of Catholics and a small but growing number of Protestants.
A relatively new phenomenon is the rising number of Muslim-born Iranians who convert to Christianity.
Issa Dibaj is the son of reverend Hassan Dibaj, a Christian convert who was jailed and later found murdered in 1994. Issa Dibaj left Iran five years ago and now lives in the U.K.
"There is another Christian minority that people know little about, these are Iranians who are born as Muslims and then later become Christians," Dibaj said. "Their number is growing day by day. [There] may be around 100,000 [of them], but no one really knows the exact number."
Such Christians run a potentially dangerous risk. Under Islamic law as practiced in Iran, a Muslim who converts to another faith can face the death penalty.
The government has refrained from executing people for this in recent years, nevertheless it has taken measure to curb proselytizing by Christians.
Some churches have been closed and reports say the authorities are putting pressure on evangelicals not to recruit Muslims or to allow them to attend services.
In September, 85 member of the Assemblies of God church were arrested during a conference in Iran. One remains in jail.
Dibaj said in spite of the restrictions, he sees a growing interest in Christianity: "[Iranians] see that the establishment which came in the name of Islam has brought them only war, rancor, hatred, and killings. At the same time, they see the message of Jesus, which is love. It attracts them through programs they see on satellite or through their Christian friends."
He added: "People are very curious, very interested. Iranians [are] open and they like to know more about different cultures, ideas, and religions. I had friends who had been prisoners of war in Iraq, at the university they were my best friends, they were very interested [about my faith], and I gave some of them the Bible."
Iranian Christians celebrate the birth of Jesus pretty much like other Christians around the world. They decorate Christmas trees, exchange gifts, and attend services. Depending on the calendar, Armenians and Assyrians celebrate Christmas on 6 January. Others celebrate usually on 24 December.
According to some reports Persia may even be the land of origin of the "Three Wise Men" who -- according to the Bible -- arrived bearing gifts for the birth of Christ. Some say they were Persian "Magi" -- members of priestly caste at the time.